1. Field of the Invention:
The present invention relates to a hot-runner mold for an injection molding, and more particularly to a hot-runner mold for obtaining a molded product constructed of a multi-layered body made of two thermo-plastic resinous materials which are different in properties from each other.
2. Description of the Prior Art:
Hitherto, in case that it is necessary to obtain the kind of molded product constructed of a multi-laminated body, each layered element thereof is formed by a suitable process for forming a film at first, and then a plurality of the thus formed films,i.e., layered elements are piled up and reheated while formed into a desired final product shape in a final shaping process using compressed air. However, in the above conventional method, since at least two forming and shaping processes are required, it is necessary to provide a plurality of installations for conducting these processes. This results in an increase of the product cost and a difficulty in forming a product having a complex shape. This is a defect inherent in the conventional method.
Although it has been considered to obtain such kind of molded product constructed of the multi-layered body by the injection molding method, it is impossible to obtain a uniformly layered and molded product having a complex shape. Since, in this case, it is necessary to provide separate outlets for injecting the resinous materials into a cavity of a product mold, i.e., a cavity plate with respect to each of two kinds of the resinous materials, the hot-runner mold is complex in its construction and large in its size. In addition to this, since the resinous materials are injected into the cavity of the cavity plate from two different outlets, it is hard to obtain a uniformly layered and molded product. This is another defect inherent in the conventional injection molding method.